Abstract
Hydrogen permeation membranes are a key element in improving the energy conversion efficiency and decreasing the greenhouse gas emissions from energy generation. The scientific community faces the challenge of identifying and optimizing stable and effective ceramic materials for H(2) separation membranes at elevated temperature (400-800 °C) for industrial separations and intensified catalytic reactors. As such, composite materials with nominal composition BaCe(0.8)Eu(0.2)O(3-δ):Ce(0.8)Y(0.2)O(2-δ) revealed unprecedented H(2) permeation levels of 0.4 to 0.61 mL·min(-1)·cm(-2) at 700 °C measured on 500 μm-thick-specimen. A detailed structural and phase study revealed single phase perovskite and fluorite starting materials synthesized via the conventional ceramic route. Strong tendency of Eu to migrate from the perovskite to the fluorite phase was observed at sintering temperature, leading to significant Eu depletion of the proton conducing BaCe(0.8)Eu(0.2)O(3-δ) phase. Composite microstructure was examined prior and after a variety of functional tests, including electrical conductivity, H(2)-permeation and stability in CO(2) containing atmospheres at elevated temperatures, revealing stable material without morphological and structural changes, with segregation-free interfaces and no further diffusive effects between the constituting phases. In this context, dual phase material based on BaCe(0.8)Eu(0.2)O(3-δ):Ce(0.8)Y(0.2)O(2-δ) represents a very promising candidate for H(2) separating membrane in energy- and environmentally-related applications.